1. Field of the Invention
The present invention is related to an ovarian cancer-specific aptamer; more specifically, the present invention is related to aptamers specific for different histologically-classified ovarian cancer cells and the applications thereof.
2. the Prior Arts
Cancer, also known as malignant tumor, is a leading cause of millions of death annually, and is also the top one most lethal disease in Taiwan over the past decade. Among the various cancers, ovarian cancer is one of the most common gynecological cancers, only next to cervical cancer, and takes the second place of the most common cancer in Taiwanese female population. Yet, in comparison to cervical cancer, with early diagnosis and proper treatment, the prognosis and survival rate of ovarian cancer are often relatively high. For instance, patients diagnosed with stage I ovarian cancer have a five-year survival rate of 89%, which drops to only 17% if diagnosed at stage IV. Unfortunately, most ovarian cancers are not easily to be diagnosed in their early stages due to insignificant symptoms, and often not until the tumor grow large enough to suppress the large intestine and result in conditions such as constipation, diarrhea, nausea, and flatulence, can the tumor be discovered. Hence, most ovarian cancers are diagnosed at stage III or later, along with tumor migration, resulting in poor prognosis.
Clinically, ovarian cancer detection methods often include virginal ultrasonic examination and Doppler ultrasound examination, which are able to determine the vascular distribution and blood flow of the tumor; however, due to the fact that ovary with ovarian cancer is similar to a normal one in size and appearance, such ultrasonic examinations still lack reliability. On the other hand, serum tumor markers, such as human chorionic gonadotropin (hCG), carcinoembryonic antigen (CEA), and α-fetoprotein (α-FP), are also used for the detection of ovarian cancer. However, most serum tumor makers having relatively poor detecting ability for early stage tumor comparing to tumor that reoccurred after surgery are not suitable for early stage detection of ovarian cancer.
In light of the fact the there are still no effective detection for early-stage ovarian cancer diagnosis, it is of great necessity to develop substitutes with high specificity to ovarian cancer cells for traditional serum tumor markers for future clinical research as well as rapid detection of ovarian cancer at its early stage, which promotes prognosis and survival rate. Meanwhile, currently, the market still lacks accurate and cost-effective markers or methods for detection and recognition of different histologically-classified ovarian cancer cells.